U.S. patent application number 10/783896 was filed with the patent office on 2005-08-25 for pigment black and dilute dye inks in ink set.
Invention is credited to McCain, Sandra Helton, Medley, John Mark.
Application Number | 20050183629 10/783896 |
Document ID | / |
Family ID | 34861362 |
Filed Date | 2005-08-25 |
United States Patent
Application |
20050183629 |
Kind Code |
A1 |
McCain, Sandra Helton ; et
al. |
August 25, 2005 |
Pigment black and dilute dye inks in ink set
Abstract
Ink sets comprising, for example, dilute cyan dye-based ink,
magenta dye-based ink and black ink of carbon black dispersed by a
polymeric dispersant. The dye inks are formulated to not
destabilize the black ink. A broader ink set is the forgoing inks
in combination with full intensity cyan, magenta and yellow inks
used to print full color photographs. The dilute ink and the black
ink are in the same printhead.
Inventors: |
McCain, Sandra Helton;
(Lexington, KY) ; Medley, John Mark; (Lexington,
KY) |
Correspondence
Address: |
LEXMARK INTERNATIONAL, INC.
INTELLECTUAL PROPERTY LAW DEPARTMENT
740 WEST NEW CIRCLE ROAD
BLDG. 082-1
LEXINGTON
KY
40550-0999
US
|
Family ID: |
34861362 |
Appl. No.: |
10/783896 |
Filed: |
February 20, 2004 |
Current U.S.
Class: |
106/31.27 ;
106/31.6 |
Current CPC
Class: |
C09D 11/324 20130101;
C09D 11/40 20130101 |
Class at
Publication: |
106/031.27 ;
106/031.6 |
International
Class: |
C09D 011/00 |
Claims
What is claimed is:
1. An ink set for inkjet printing comprising at least three
separate inks in separate chambers in an inkjet printhead with exit
orifices for each said chamber, said ink in said chambers being
subject to some moderate entry of ink from other of said chambers,
said ink set comprising a first dilute color ink of a first color
in a first of said chambers, a second dilute color ink of a second
color in a second of said chambers, and a black ink comprising
black pigment dispersed in water in a third of said chambers, said
first ink and said second ink being compatible with said black ink
when in said black ink in moderate amounts.
2. The ink set of claim 1 in which each said first dilute color ink
and said second dilute color ink have total color of dye in amount
of 0.6 percent or less by weight of the ink of said dye.
3. An ink set comprising: a first aqueous ink consisting
essentially of dye as a colorant of a first color in amount of 0.6
percent or less by weight of the weight of said first ink, a second
aqueous ink consisting essentially of dye as a colorant of a second
color in amount of 0.6 percent or less by weight of the of said
second ink, and an aqueous black ink comprising carbon black.
4. The ink set as in claim 3 in which said carbon black is
dispersant in said black in by a polymeric dispersant.
5. An ink set for inkjet printing comprising a first full intensity
color ink having dye as colorant, a second full intensity color ink
having dye as colorant, a third full intensity color ink having dye
as colorant, a first dilute color ink having dye as colorant, a
second dilute color ink having dye as colorant, and a black ink
comprising dispersed black pigment, wherein said first dilute color
ink and said second dilute color ink are compatible with said black
ink when in said black ink in moderate amounts.
6. The ink set of claim 5 in which said first dilute color ink,
said second dilute color ink and said black ink are contained in
separate chambers of a first printhead, each having a exit orifice,
said first full intensity in, said second full intensity color ink
and said third full intensity color ink being in at least one
printhead separate form said first printhead.
7. The ink set of claim 5 in which said colorant of said first
dilute color ink and said colorant of said second dilute color ink
each is in amount to produce an optical density of less than 60% of
the optical density of one of said full intensity inks having a
corresponding color.
8. The ink set of claim 6 in which said colorant of said first
dilute color ink and said colorant of said second dilute color ink
each is in amount to produce an optical density of less than 60% of
the optical density of one of said full intensity inks having a
corresponding color.
Description
TECHNICAL FIELD
[0001] This invention is directed to ink sets for printing a range
of color intensities and hues, along with black parts, as is for
the employed inkjet printing of digital, color photographs.
BACKGROUND OF THE INVENTION
[0002] With the increased emphasis on the generation of
photographic images using inkjet technology, a strong focus has
recently been placed on specific printing systems for photo
printing. To this end, several inkjet manufacturers have introduced
printers capable of printing using six, seven, or as many as eight
colors to generate photo-realistic inkjet prints that exhibit
excellent print quality and permanence (archivability).
[0003] This has typically been accomplished by adding one or more
photo cartridges containing dilute cyan and magenta, and,
optionally, black inks to the existing cyan, magenta, and yellow
(CMY) ink set. Each cartridge is based either on dye-based ink
technology or on pigment-based ink technology.
[0004] Typically, where dye inks and pigment inks are used together
in an ink set, incompatibility of the two inks is ignored or
considered desirable. Usually the dye inks and the pigment inks are
in separate cartridges. When the inks are incompatible they will
not flow together, and prevention of such flowing together, often
termed bleed, is desirable in printing operations using standard
inks. When a pigment ink is incompatible with another ink, the
pigment is destabilized and settles from the liquid of the ink,
which avoids bleed.
[0005] Pigmented black ink, used primarily on plain paper, is
superior to dye-based black inks for some applications. The
insolubility of pigment such as conventional carbon black renders
the pigment less likely to migrate once it is printed on paper.
This quality provides enhanced water resistance on plain paper and
allows the generation of text and graphics with enhanced edge
acuity over dye-based black inks.
[0006] Dye based color inks, on the other hand, typically exhibit
much brighter color and higher resistance to smearing than
pigment-based counterparts. As a result, they are often preferred
in some applications.
[0007] Depending on the application, these divergent attributes
must often be compromised because of the requirement that a
particular printhead contain only pigment-based inks or dye-based
inks to avoid incompatibility between the two inks.
[0008] This invention provides an ink set in which a full range of
colors can be printed while two dye-based colors and pigment black
are in a single printhead.
DISCLOSURE OF THE INVENTION
[0009] This invention employs the combination of two dilute
dye-based inks, such as dilute cyan and magenta inks, with
polymer-dispersed pigmented black ink in the same printhead. It can
also be applied to other ink combinations. Specifically, a
printhead containing four inks, namely dye-based CMY with pigmented
black ink, would also fall under the scope of this invention.
[0010] The printhead of this invention is to be used along with
full intensity inks, such as CMY inks, in one or more separate
printheads. This permits full color printing of images,
specifically digital photographs. The resulting image has the
strong color effects of dye colorants and the pleasing dark effects
of pigment black with good image definition.
[0011] Broadly, this invention is an ink set of at least two,
dilute (low intensity) dye-based inks and dispersed pigment black
ink. Additionally, this invention is such an ink set contained in
separate compartments in a single ink jet printhead, all inks in
that printhead being compatible with the black ink. This invention
also encompasses a dye set of full intensity color inks separated
from a printhead having at least two dilute dye-based inks and
dispersantdispersed pigment ink.
[0012] Dilute inks in accordance with this invention typically have
an optical density of 60% or less of the optical density of
corresponding full strength ink (corresponding inks are inks of
similar or identical color (hue)). Typical dilute inks have a dye
content as essential colorant of 0.6 percent or less of the weight
of the ink. Pigments in accordance with this invention are
typically standard carbon black, with the dispersant being a
polymer which may take variety of forms. Self dispersed carbon
blacks are known. These can add to overall density and the pigment
ink in accordance with this invention may well be a mixture of
self-dispersed carbon black and polymer-dispersed carbon black.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] This invention will be described using the accompanying
drawings, in which
[0014] FIG. 1 is a top, perspective view with cover omitted of a
printhead illustrative of that referred which might contain the
inks of this invention, and
[0015] FIG. 2 is a bottom, perspective view of the printhead of
FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] This invention describes the simultaneous use of dye-based
inks and pigment-based inks in the same printhead. The benefits of
this technology are substantial. Foremost among the advantages of
this system is the ability to produce optimized prints on a variety
of media without the necessity of purchasing special printheads for
divergent applications. Additionally, this technology eliminates
the requirement that the consumer physically change the printheads
in order to achieve optimum results.
[0017] In order to accomplish this marriage of pigment and dye in
the same printhead, it is necessary to control the formulations of
all of the inks. To this end, several characteristics of the inks
have been identified that are necessary for proper function in this
system. The main concern resulting from the interaction of the
dye-based inks with the pigment-based inks is the destabilization
of the pigment dispersion by components in the dye-based ink.
[0018] While the dye molecules in the inks may cause some problems,
other components in the system are more problematic. Often,
multi-valent salts of magnesium or other metals are added to the
dye-based inks in order to improve print quality by preventing
bleed. To ensure that the function of the pigmented ink is not
impaired, it is necessary to optimize the dye-based inks without
the use of these salts. On the other hand, pigmented inks are often
formulated with the addition of latex binders in order to improve
smear resistance. These dispersions are also susceptible to
destabilization by the dye-based ink, and should be avoided in
order to ensure proper function of all of the inks jetting from the
printhead.
[0019] Black inks generally consistent with this invention are
described in U.S. Pat. No. 6,646,024 B2, assigned to the assignee
of this invention. One ink is a mixture of polymer dispersed carbon
black and self-dispersed carbon black, and such a mixture is an ink
consistent with this invention. Dispersants consistent with this
invention are described in U.S. Pat. No. 6,652,634, assigned to the
assignee of this invention.
[0020] The following tables detail specific examples of inks
illustrative of this invention. The following abbreviations are
used in the tables:
[0021] ProJet Cyan 1--A commercially sold cyan dye, the dye
colorant being Direct Blue 199 in an aqueous solution.
[0022] Magenta dye--The following describes representative magenta
dyes. 1
[0023] Wherein M1 comprises Cu, Ni, Fe, or Cr, and M comprises --H,
--Na, --Li, --K, or an optionally substituted ammonium ion.
[0024] Hampene Na3T--A commercially sold trisodium
ethylenediaminetetracet- ic acid (alternative known as trisodium
EDTA), a chelating agent.
[0025] Proxel GXL--A commercially sold biocide commonly used in
inkjet inks.
[0026] TEA--Triethanolamine, a buffer.
[0027] BES--A commercially sold N,N-bis(2-hydroxyethyl)tuarine or
N,N-bis(2-hydroxyethyl)-2-aminoethane sulfuric acid, a buffer.
[0028] SILWET 7600--A commercially sold carbon, linear methyl
mutiethyloxpropyl siloxane, a surfactant.
[0029] 2-P--2-pyrrolidone, a cosolvent.
[0030] TMP--Trimethyolpropane, a cosolvent.
[0031] EG4--Tetraethylene glycol, a cosolvent.
[0032] PEG400--Polyethylene glycol, 400 weight average molecular
weight, a cosolvent.
1 Ink Formula 1 Dilute Cyan Dye By Weight Percent DI Water Balance
ProJet Cyan 1 0.44% Hampene Na3T 0.10% Proxel GXL 0.15% TEA 0.25%
BES 0.20% 1,2-Hexanediol 3.00% SILWET 7600 0.50% 2-P 6.25% TMP
6.25% 1,5-Pentanediol 6.25%
[0033]
2 Ink Formula 2 Dilute Magenta Dye By Weight Percent DI Water
Balance Magenta Dye 0.55% Hampene Na3T 0.10% Proxel GXL 0.05%
1,2-Hexanediol 4.00% SILWET 7600 0.50% 2-P 8.00% EG4 6.00%
Tri-Propylene Glycol 6.00%
[0034]
3 Ink Formula 3 Representative Pigment Black Formulation: % by
Weight Self Dispersant Carbon Black 2.17 Dispersant Dispersed
Carbon Black 1.08 PEG400 9.0 2P 9.0 1,2 Hexanediol 2.6
Hexylcarbitol 0.40% DI Water Balance
[0035]
4 Ink Formula 4 Representative Full Intensity Dye FORMULATION % BY
WEIGHT DI Water Balance ProJet Cyan 1 3.0 Dissolvine Na3T 0.10
Trimethylolpropane 6.25 2-Pyrrolidone 6.25 1,5-Pentanediol 6.25
1,2-Hexanediol 3.00 Proxel GXL 0.15 TEA 0.25 BES 0.20 SILWET L-7600
0.50 Magnesium Nitrate Hexahydrate 0.30 Sodium Hydroxide to pH 7.5,
OR 0.00 to 0.10 Glacial Acetic Acid down to pH 8.2 0.00 to 0.10
[0036] Ink Formulas 1, 2 and 3 represent the two dilute, low
intensity inks and the black ink of this invention. These low
intensity inks are compatible with the black ink. Typically, the
black ink will be somewhat diluted in intensity, but it may be full
intensity. Other dilute color inks may also be included.
[0037] Ink Formula 4 represents the full intensity ink pertinent to
this invention. Other full intensity inks pertinent to this
invention would have magenta dye, yellow dye and may have other
colorants. No novelty for the full intensity inks per se is
necessary with respect to this invention.
[0038] FIGS. 1 and 2 are based on illustrations of U.S. Pat. No.
5,926,195, assigned to the assignee of this invention. The
cartridge shown is illustrative of a printhead with which this
invention may be employed. As shown in FIG. 1 the printhead 1 has
three chambers 3, 5, and 7 in which two dilute color inks and one
pigment black ink care kept. Similarly, in a separate cartridge the
three chambers 3, 5, and 7 each contain full intensity inks of
different colors. Orifices 9, 11, and 13 shown in FIG. 2 permit the
ink in each chamber to leave the chamber for printing. Each orifice
9, 11, and 13 is in separate liquid communication with one of the
chambers 3, 5, and 7. As is widely practiced, the printhead 1 has a
thermal chip or other ink discharge device (not shown) which
receives ink from orifices 9, 11, and 13 and applies to ink in
small dots or pels on the media being imaged.
[0039] Ink exits the printhead 1 from the same side (the side
having orifices 9, 11, and 13 in FIG. 2) and generally from
locations close together. Moreover, during non-use the printhead is
brought to a location at which the exit ports are capped to prevent
evaporation of the ink. Accordingly, inks in the typical printheads
are subject to some moderate transfer of ink between chambers, such
as chambers 3, 5, and 7. In accordance with this invention, the
dilute inks must be compatible with the black inks in the moderate
amounts which can be transferred across the printhead.
[0040] Experimental data shows stability of the foregoing mixtures
of dilute dye-based inks and the pigment-based ink. Two inks, one
black, were mixed at various ratios and stored at 60.degree. C. for
24 hours. The particle size of the resulting liquid was then
measured. Any observed increase in particle size in this experiment
indicates instability. The presence of salt (Mg(NO.sub.3).sub.2) in
a cyan ink leads to much greater particle size growth in this
test.
[0041] A second experiment measures the impact of the contamination
of pigmented black ink with dye-based cyan ink in the same
printhead. After subjecting the cartridges to severe printing
conditions, the number of missing black nozzles was measured. For
this experiment, polymer-dispersed pigmented black ink formulated
without the addition of latex binder was employed. The same levels
of salt (Mg(NO.sub.3).sub.2) were employed in these cyan inks as in
the particle-size test. The presence of salt in the cyan ink causes
a substantial increase in the number of black nozzles that are
missing after severe printing.
* * * * *